Mapping Mountains – Trimble Surveys – Y Mynydd Du

10.07.14  Cerrig Coegion (SN 790 176), Tyle Garw (SN 784 178), Disgwylfa (SN 815 178), Carreg Goch (SN 818 170) and Twyn Walter (SN 828 175).

Carreg Goch (SN 818 170)

To the south of the escarpment edge that gives the higher hills of Y Mynydd Du their beauty is a land unrivalled in the whole of Wales, as within its midst is the remotest hill and the remotest point from a paved public road in mainland Wales.  The sense of remoteness is relative, as by Scottish standards neither is exceptional, but for the country where the majority of my hill walks take place, both are without equal.

I wanted to do this walk for a number of years, ever since the maps were opened and studied and measurements taken and criteria adopted.  The map study culminated in a hill list named Y Pellennig (originally the Pellennigs) which was published on Geoff Crowder’s website in late 2011 and which is soon to be jointly produced with Aled Williams.

Initially I wanted to find the point in Wales that is farthest from a paved public road, I soon turned my attention to compiling a list of remote Welsh hills.  During compilation I wondered where the remotest spot and hill would be found, my first thoughts led me toward the great expanse of emptiness of the Elenydd, I was surprised to find that the southern lands of Y Mynydd Du included these two special places.

This walk was suggested to Mark a couple of months ago as a possibility as he wanted to visit south Wales to get better photographs for the 2^nd edition of Y Pedwarau that is planned for publication.  He also wanted a walk that combined Dewey and Pedwar hills, there are few possibilities in south Wales that give a good length walk with Dewey and Pedwar bagging, but todays walk is one of them.

We travelled south as the sun shone and the blue of the sky intimated a perfect day to venture in to such remote surroundings.  The ideal way to visit the five hills listed above is to traverse the mountain range, by doing so the hills of Carn Fadog (SN 767 171), Foel Fraith (SN 756 183) and Garreg Lwyd (SN 740 179) can also be visited.  Having only one car and no means to make the circuitous journey back, we opted for a there and back route. 

The easiest way toward this remote land from the east is to follow a good track from close to the Dan yr Ogof show caves in Glyntawe, this track bisects the three 500m Deweys and heads off in to the heart of wilderness.  As we planned to use this track for our outward journey we decided to ascend the lower southern ridge of Fan Hir and circumvent the three Deweys before joining the track and the remote land beyond.

Before getting our boots on we stopped to take photos of Cribarth (SN 831 143) before joining the hordes of school children and happy families as they descended upon the show caves, as most headed underground to admire the architecture that was carved out millions of years ago, we headed in to the café for coffee and cake!  Once nourished we drove to a car park opposite a pub brandishing a large ‘Closed’ sign which is on the A4067 a few hundred metres north of the show caves entrance.

The shapely profile of Cribarth (SN 831 143)

Adjacent to this car park is a path that forms part of the Beacons Way, which is a 152km (95 mile) linear walk across the Brecon Beacons National Park.  We soon gained height up the southerly ridge of Fan Hir above Cwm Haffes, to our north-east the rounded profile of Fan Gyhirych dominated the view, whilst further south the shapely mass of Cribarth overlooked the valley.

Fan Gyhirych (SN 880 191) the western outlier of Fforest Fawr

This route up relied on there being a path, or alternatively, easy ground, contouring around the upper part of the Afon Haffes, thankfully we picked up a good sheep track that led us toward a waterfall named Sgwd Ddu on the Ordnance Survey map.  On the way I found a hole to put my foot in and Mark plunged in to an unsavoury bog.

Heading toward Sgwd Ddu, a waterfall situated in a quiet area of Y Mynydd Du

A few kilometres beyond the horizon is the remotest land in mainland Wales

Mark making progress through the grassland with the slender cascade of Sgwd Ddu on the left of photo

Although this route in to the hills is not as easy as the track that bisects the three Deweys, it gave us the opportunity to see part of this land that is probably seldom visited, and as we looked across to Sgwd Ddu with its cascading water forever falling, a Heron silently appeared loping upstream toward the waterfall.  We crossed the Afon Haffes beyond the waterfall and headed west directly toward a large fenced off bog named Waun Fignen Felen.  We circumvented this on its northern side and smiled as we came across a foot stile directing walkers directly in to the morass of bog, we wondered if this had been put there by a Warden for an April fool’s joke!

Crossing the Afon Haffes

Beyond the bog we joined the track and came across a small party of youngsters who were traversing the hills as part of their silver award on the Duke of Edinburgh Award scheme.  As we chatted I looked west in to a large expanse of grassland, seemingly without fences, remarkably the only fence during nine hours of walking and surveying we came across was the one around the bog that we had just passed, otherwise this whole land is open for sheep and horses to roam and for the unwary walker to get lost.

The track passed one or two pools as it headed down to cross a stream, before heading uphill to cross the shoulder of Twyn Tal y Ddraenen, as height was gained we left the track and joined a sheep path heading south on an intermittent ridge, before venturing west in to a land of grass wilderness.  Even with the comfort of a hand-help GPS and a Trimble we kept checking the map and realising that the first hill we were aiming for was seemingly forever further on.

Disgwylfa (SN 815 178) rises above one of the small pools near to our inward track

The route from the intermittent ridge which is the southern part of descending land from Twyn Tal y Ddraenen took us directly toward the remotest point in the whole of mainland Wales, this is the spot of land that is farthest from any paved public road, this point is close to the apex of the northern ridge of Cerrig Coegion, to within a few metres its grid reference is SN 79220 18316.

Mark aims directly ahead toward the remotest point in mainland Wales

Mark led the way with his GPS in hand, striding out over the land like an intrepid traveller from a bygone age.  However, he was rather underwhelmed by the spot of land we reached, probably as he has so much experience of walking in Scotland, where the concept of Welsh remoteness would be a necessity to get to the majority of hills.  Once Mark had declared he had found the remotest point he stuck his walking poles in the ground and I then used the Trimble to hone in on the exact spot.  It had taken us three hours to get here, the customary photos were taken and I gathered five minutes of data with the Trimble, a new experience as this was neither a summit nor a bwlch, just a patch of land as far from a paved public road that one could get to in mainland Wales. 

Walking poles and Trimble mark the spot - the furthest point from a paved public road in mainland Wales

The Trimble GeoXH 6000 gathering data at the remotest spot in mainland Wales

Tyle Garw (SN 784 178) from the lower slopes of Cerrig Coegion

As the Trimble gathered data Mark headed up to the summit of our first hill of the day; Cerrig Coegion, I soon joined him.  Cerrig Coegion is the 3^rd remotest hill in mainland Wales, with only Foel Uchaf (SN 770 654) in the Elenydd and Tyle Garw (SN 784 178) surpassing it.  We gathered data on the high point at the position where the 474m spot height appears on the map; we then visited the trig pillar and gathered more data at the high point just to the west of the trig, as this looked like a contender for overall high point.  The whole summit area had limestone rocks scattered over it, with distant views across the Severn estuary to Devon and the south-westerly lands of England.

Mark heads off toward the first summit of the day; Cerrig Coegion

Mark on the summit of Cerrig Coegion, the 3rd remotest summit in mainland Wales

Gathering data on the summit of Cerrig Coegion

The 471m trig pillar is positioned just to the south of the summit of Cerrig Coegion

Our next hill was Tyle Garw; the remotest hill in mainland Wales.  We took a direct route past a pool and up to its summit, however unremarkable a spot when viewed as a singular summit; it was nonetheless a spot I had wanted to visit for a number of years.  As the Trimble gathered five minutes of data I looked out in all directions, all I could see were hills and open land, with one exception being to the south where England’s green and pleasant land could just be distinguished.  To the north a large bank of cloud over the higher Mynydd Du peaks was now heavier in colour and had descended upon the summit of Fan Brycheiniog, these higher hills had been bathed in shadow all day, whilst we had been on the periphery of the cloud bank in sunshine.

Heading toward Tyle Garw (SN 784 178), the remotest summit in mainland Wales

Mark on the summit of Tyle Garw - the remotest summit in mainland Wales

Gathering data at the summit of Tyle Garw

As we left the summit of Tyle Garw it was 5.45pm, we had been walking and surveying for five hours, we now had to retrace some of our inward route and get back on to the track that would take us up toward Disgwylfa and the three remaining Deweys.  By now the sun had lowered in the sky and those magical evening colours that are so sought after were just beginning to emerge.  As the open land of tussock and bog was crossed the lowering sun toward the bank of cloud had cast emerald on the grassland, we stopped for a moment to savour the colour as a Heron flew westward, effortless in flight with its distinguishable profile caught in memories eye with the browns and greens of the hills as backdrop.

Lowering sun highlighting the greens of  the southern lands of Y Mynydd Du

Heron caught mid-flight

Soon the two remote Pedwar hills disappeared from eye as we re-crossed the intermittent ridge of Twyn Tal y Ddraenen and re-joined the inward track, only stopping to watch a number of horses as they ran across the land.

Last view of Tyle Garw

Cerrig Coegion and Tyle Garw

One of many horses that roam the southern lands of Y Mynydd Du

The track led us up toward the last three summits of the day.  However, we had to leave the comfort of the track and branch right to slowly make our way up to the summit of Disgwylfa, a fine hill, with a limestone bouldered summit.  As the Trimble gathered data I looked out as evening light enhanced the glow of dark grey, white and blue in the sky.

Gathering data at the summit of Disgwylfa

Our next summit and penultimate of the day was Carreg Goch, a small path led the way past limestone outcrops down toward a large sink hole that splits the area of the bwlch in two.  At 558m on the map this hill was the highest of the day, it has a fine summit, again comprising an assortment of limestone boulders and rocks.  The Trimble sat on the highest, gathering data as we both took photos and looked down and across to the last summit of the day; Twyn Walter.

Mark taking a photo as the Trimble gathers data on the summit of Carreg Goch

The route from Carreg Goch to Twyn Walter does have an occasional sheep track to ease passage; otherwise it is pathless, but never difficult.  The magical hour of evening’s illuminated colour had gone by the time we reached its summit, replaced by the darkening silence of afterglow.  I removed the small summit cairn to place the Trimble on the highest point of the hill, and replaced the cairn after five minutes of data had been collected.

Gathering data at the summit of Twyn Walter, a hill that probably needs deleting from the Dewey list

We then re-joined the track and descended towards the valley as the full moon shone and the remaining cloud etched itself in pink, sometimes ablaze in shapely colour silhouetting a single small tree on the horizon. 

Evening's colour silhouetting a single small tree

The walk had taken nine hours and had covered 20.3km (12½ miles) with 715m (2,346ft) of ascent.  We arrived in Welshpool at 11.45pm where Mark had a quick rejuvenating cup of coffee before driving back home.  A great day! 

Survey Result:

Cerrig Coegion (significant name change)

Summit Height:  473.4m (converted to OSGM15)  

Summit Grid Reference:  SN 79087 17673

Bwlch Height:  c 417m (interpolation)

Bwlch Grid Reference:  SN 79551 18705 (interpolation) 

Drop:  c 56m (Trimble summit and interpolated bwlch)

Dominance:  11.91% (Trimble summit and interpolated bwlch)

Tyle Garw

Summit Height:  467.3m (converted to OSGM15)

Summit Grid Reference:  SN 78499 17819

Bwlch Height:  c 426m (interpolation)

Bwlch Grid reference:  SN 78703 17360 (interpolation)

Drop:  c 41m (Trimble summit and interpolated bwlch)

Dominance:  8.84% (Trimble summit and interpolated bwlch) 

Disgwylfa

Summit Height:  543.5m (converted to OSGM15, Trimble GeoXH 6000)

Summit Grid Reference:  SN 81565 17897 (Trimble GeoXH 6000)

Bwlch Height:  c 503m (interpolation)

Bwlch Grid Reference:  SN 81562 17267 (interpolation)

Drop:  c 41m (Trimble GeoXH 6000 summit and interpolated bwlch) 

Dominance:  7.45% (Trimble GeoXH 6000 summit and interpolated bwlch)

Carreg Goch

Summit Height:  558.3m (converted to OSGM15, Trimble GeoXH 6000)

Summit Grid Reference:  SN 81887 17029 (Trimble GeoXH 6000)

Bwlch Height:  c 492m (interpolation)

Bwlch Grid Reference:  SN 81967 18317 (interpolation)

Drop:  c 66m (Trimble GeoXH 6000 summit and interpolated bwlch) 

Dominance:  11.82% (Trimble GeoXH 6000 summit and interpolated bwlch)

Twyn Walter

Summit Height:  502.1m (converted to OSGM15) (significant height revision)

Summit Grid Reference:  SN 82837 17506

Bwlch Height:  475.9m (LIDAR)

Bwlch Grid Reference:  SN 82597 17917 (LIDAR)

Drop:  26.25m (Trimble GeoXH 6000 summit and LIDAR bwlch) (500m Twmpau reclassified to 500m Sub-Twmpau) (Dewey deletion) (Dodd deletion)

Dominance:  5.23% (Trimble GeoXH 6000 summit and LIDAR bwlch)

For further details please consult the Trimble survey spreadsheet click {here}